Carburetor



April 25, 1933. LORENZ 1,905,988

CARBURETOR Filed Aug. 11 1930 Patented pr. 25, 1933 UNITED STATES PATEIS{TZ;OFFICE zum: LORENZ, o1 STU'IIGA.RT, GEBM.ANY ASSIGNOR T fiOBER'I 1'305C11 AKTIENGE- SELLSCHAFT, 02 STUTTGART,

CA.RBURETOR Applicationfiled August 11, 1930, Seria1 N0.

. Thd pr sent invention relates to spray carburetors of the type having an air throttle and a float chamber in which the air space of the float chamber is connected to one choke tube by an air duct so that a vacuum is main- .tained in said air space to draw fuel ftom the tank into the float chamber, whilst the fuel space of the float chamber is connected to a second o1 third auxiliary choke tube in whicl1 a higher vacuum obtains than in the first choke tube. When the air throttle of this carburetor is olosed such a high vacuum is producecl in the mixing chamber that the fuel in the float chamber begins to vaporize vigorously whereby the vacuum in the air sp'ace of the float chamber is reduced and the fuel can escape from the nozzle of the main fuel pipe. This fuel collecfs in the mixing chamber and under the circumstances vapors sucked from the air spabe of the float chamber can also be deposited therein. As a result when the air throttle is subsequently opened the mixture is much too rich and the consump tion of fuel is unnecessarily great.

According to the present invention, the mixing chamber is also closed from the engine by a throttle to such an extent When the air l throttle is closed that the vacuum arising in the mixing chamber only reaches a degree necessary f0r keeping the fuel level at the required height in the float chamber, therefore to suck the fuel with centainty from the supply tank.

One form of construction according to the invention is shown by way of example in the accompmnying drawing.

A mixing tube a has a main choke tube b in which is disposed an auxiliary choke tube c. The throat of the choke tube b is counected to the ai1 space of the flbat ohamber e by a passage d. A pipo f l1aving a constrictio n g leads from the fuel space of this float ohamber to the throat of the choke tube c. The air throttle valve h is connected to a second throttle valve k behind o1 in rear of the choke tubes -by a rod z. 'lhis throttle k has a slot' m formed therein fro'm which projects the'end of a pipe n having a coustriction o for light running when the throt- 474,522,a1u1 1iGermany September 2, 1929.

engine. This va cuum however cannot act so strongly in the mixing chamber that the fuel in the float chamber is excessively vaporized 'and can thereby flow out 0f the main' pipe f thr0ugh the reduction of -the vanuum taking place in the air space of the float chamber. 1The degree of Vacuum in the mixing chamber is determined by the free crosssection ofthe connection between the mixingg; chamber and the chamber behincl the throttle k and in addition by the cross-section of the opening p.

The arrangement for light running can also be constructed in the manner usual in the normal carburetors in which air is sucked out of the mixing chamber through the, mouth of the pipe n through a groove on the throttle valve k 01' by partly opening the throttle valve.

What I claim is l. A self-feeding carburetor comprising a casing which includes a mixing chambe r, at least two choke t ubos adapted to produce different degrees of vacuum for any given degree of engine suction, a fioat chamber the air space of which is connected to the choke tube of lower vacuum and the fuel space to tl1e choke tube of higher vacuum, an air throttle in advance of said choke tubes and a mixture throttle in rear of said choke tubes, the mixture throttle being operatively connected to said air throttle so that When the air throttle is closecl, tl1e passage from the mixing chamher t0 the engine is partly opcin but is sufliciently closed to prevent the 'vacuum in tho mixing chamber from appreciably exceeding that required to maintain the fuel level in tl1e float chamber.

2. A self-feeding carburetor comprising a casing which includes a mixing chamb.er a!nd having an opening to atmosphere acljacent the engine end of said mixing chamber, at least two choke tubes adapted to produce differenfi degrees of vacuum for-any given degree f engine suction, a float chamber the air space 0f which is connected to the choke tube of lower vacuum and the fuel space to the 5 choke tube of higher vacuum, an an throttlein advance of said choke tubes, mmixture thrdttle having an opening formed therein located in rear 0f said choke tubes and associated With said air throttle and an auxiliary fuel supply duct for slow running purposes leading from the float chamber to said opening in the mixture throttle.

3. A self-feeding carburetor comprising a casing which includes a mixing chamber, at least two choke tubes adapted t0 produce different degrees of vacuum for any given degree of engine suction, a float chamber the air space 0f which is connected t0 the choke tube of lower vacuum und the fuel space to the choke tube of higher vacuum, an air throttle in advance of said Choke tubes, a mixture throttle hzwing an opening formed therein located in rear 0f said Choke tubes and being operatively connected t0 said air throttle, an auxiliary fuel supply duct f01' slow running purposes leading f1om the fl0zit chamber t0 said opening in the mixture throttle, and an air orifice directly connecting the mixing tube to the atmosphere in advance of said mixture throttle f0r supplying air for light running and for fixing the vacuum in said mixing tube.

In testimony whereof I have hereunto affixed my signature.

MAX LORENZ. 

